The present invention concerns jumping surfaces used with trampolines to increase safety and performance for users.
In the past, trampolines have been used for a variety of athletic and recreational purposes. However, thousands of injuries have resulted when persons jumping on a trampoline have landed on the rebounding surface while in an awkward or incorrect body position. These “on-bed” injuries, according to some medical studies, represent the majority of trampoline-related emergency room visits. The U.S. Consumer Products Safety Commission (CPSC) reports that in 1999 approximately 110,000 people were treated in emergency rooms for trampoline related injuries. Even though this number is half that of play structure/swing set injuries, some in the medical community have called for a ban on the sale of backyard trampolines. The CPSC and the AAOS have taken a more responsible and measured approach to problem.
Recognizing that other outdoor activities that are more injurious, like bicycling, would fill the void left by backyard trampoline play, these organizations have instead called for safety improvements to help reduce the disturbingly large number of trampoline injuries.
One approach to reducing trampoline injuries has been to form a wall around the perimeter of a trampoline bed or mat so that when a jumper lands too near the edge, the wall prevents the jumper from falling off. Examples are shown in U.S. Pat. Nos. 5,399,132 and 6,053,845, which are incorporated herein by reference. However, these devices do not directly address injuries that result when users impact the rebounding surface incorrectly or while in an awkward position. A second approach, the use of a harness (worn by the jumper) suspended by elastic cords above the rebounding surface, is an effective way to reduce on-bed, or rebound surface impact injuries. However, such harnesses are designed for safely teaching users advanced acrobatics on high-performance competition trampolines by trained professionals, making them largely inappropriate for low-performance backyard trampolines that are used almost entirely for basic jumping activities and not for advanced acrobatics.
All things being equal, a bed or mat with less tension is more forgiving when a jumper first contacts its surface; it absorbs the impact more slowly and will thus reduce the severity and quantity of on-bed injuries. Nevertheless, injuries suffered during an impact with the rebounding surface are still occurring in large numbers on backyard trampoline beds even though these beds are designed to be less responsive and to have less initial surface tension than gymnastic grade, competition trampoline beds. Reducing bed-impact injuries, especially those that occur on backyard trampolines, was one purpose of the present invention, though the art can be used with all trampolines.
Low performance backyard trampolines are used very differently than high performance trampolines used by skilled competitors for training and competition. For instance, many on-bed backyard trampoline injuries occur when multiple jumpers are using the trampoline at the same time as reported in the NEISS data compiled by the CPSC. Because children enjoy playing together most families allow more than one child to jump at the same time even though this practice is strongly discouraged by trampoline manufacturers, the CPSC, and others experts. Competition trampolines are used almost exclusively in disciplined environments for the structured teaching of specific skills. In contrast, backyard trampolines are largely used for fun, unstructured, imaginative play activities that are relished by kids and recommended by child development experts who understand that daily physical activity significantly enhances learning ability and that kids need activities to counterbalance today's over-structured and sedentary lifestyles. Unfortunately, these unstructured trampoline activities generate numerous on-bed injuries when jumpers land on the rebounding surface in an awkward body position or when a jumper lands on a trampoline bed that has been preloaded with the energy from other jumper impacts.
There thus remains a need to reduce the quantity and severity of on-bed injuries that result from such playful activities.
In the applicant's U.S. Pat. No. 6,840,891 (issued Jan. 11, 2005), which is incorporated herein by reference. The aforementioned and other problems are partially resolved in a trampoline system with systematically phased spring elements. Briefly, springs or other elastic connectors used to support a rebounding mat within the frame of a trampoline or the like are attached using methods that systematically vary the tension (or the travel distance required to reach limit of elasticity) between adjacent (or sets of adjacent) springs. These spring attachment methods increase the time it takes a trampoline to absorb a given amount of energy, thus increasing the shock absorption time and thereby reducing the likelihood of an injury. Further, for an existing trampoline that already deploys springs of uniform elastic properties, the aforementioned improvement requires replacing every other spring with softer springs
However, replacing alternating springs with softer springs reduces the rebounding performance, which while making the trampoline generally safer, also reduces the the potential rebounding performance from the level that would be desired by more skilled or experienced users, who would prefer to bounce higher. In any trampoline for home use, the elasticity and tensioning of the springs, which control the rebounding performance, are generally selected to be suitable for participants of average weight and athletic ability.
For more skilled athletes, it is desirable to provide a trampoline system that affords the opportunity to bounce higher on each rebound, yet at the same time also be more forgiving in preventing injury. The potential for injury being increased, as a user falling from a higher bounce will have a larger acceleration when hit the rebounding mat.
An additional purpose of the present invention is to provide a trampoline system that can accommodate users having a wide range of weights and athletic abilities, with the option to further customize the trampoline rebounding performance to suit individual participants. An additional object of the present invention has been to provide a means for such customization without the need to remove and replace springs, as well as minimize the time required to make such a change. As such, a customizable trampoline system when shared among different users is likely to undergo a change in set up.
Therefore, a further object of the present invention has been to provide an adjustable spring tensioning system wherein the tension setting is readily apparent to participants.